That was the caption on a picture tweeted out by Richard Sherman that depicts the Seattle cornerback taunting Tom Brady after the Seahawks' 24-23 victory over the New England Patriots on Sunday. While this certainly isn't a shining beacon of sportsmanship, it embodies the brash and bodacious nature of the NFL's most overlooked defense.

But there's plenty of note going on in the Seahawks' 4-3. On rushing downs, the Seahawks switch to something resembling a 3-4: They have four down linemen, but three of them are defensive tackles—big ones, like Alan Branch, Red Bryant, and Brandon Mebane. Together the three weigh 959 pounds. A pass-rushing end, usually Chris Clemons, will stand apart from the three linemen and try to beat the tackle one-on-one. The Seahawks call this man the "Leo," presumably because it sounds cool.

On third downs or in obvious passing situations, Seattle might throw two Leos into their formation, with rookie phenom Bruce Irvin (who has 4.5 sacks already, despite playing only a third of Seattle's defensive snaps) playing opposite Clemons (who has 5.5 sacks). Then the Seahawks' line looks like the "wide nine" everyone talked about with the Eagles last year, except it actually works